package com.atguigu.day10;

import com.atguigu.bean.WaterSensor;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.tuple.Tuple1;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.functions.AggregateFunction;
import org.apache.flink.table.functions.TableFunction;

import static org.apache.flink.table.api.Expressions.$;
import static org.apache.flink.table.api.Expressions.call;

public class Flink03_SQL_UDF_AggFun {
    public static void main(String[] args) {
        //1.获取流的执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        //2.从端口读取数据并转为WaterSensor
        SingleOutputStreamOperator<WaterSensor> waterSensorStream = env.socketTextStream("localhost", 9999)
                .map(new MapFunction<String, WaterSensor>() {
                    @Override
                    public WaterSensor map(String value) throws Exception {
                        String[] split = value.split(",");
                        return new WaterSensor(split[0], Long.parseLong(split[1]), Integer.parseInt(split[2]));
                    }
                });

        //3.获取表的执行环境
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);

        //4.将流转为表
        Table table = tableEnv.fromDataStream(waterSensorStream);

        //5.不注册直接在TableAPI中使用
     /*   table.groupBy($("id"))
                .select($("id"),call(MyAvg.class, $("vc")))
                .execute()
                .print();*/

       //先注册然后在TableAPI中使用
        tableEnv.createTemporarySystemFunction("myAvg", MyAvg.class);
     /*         table.groupBy($("id"))
                .select($("id"),call("myAvg", $("vc")))
                .execute()
                .print();
*/
         //在SQL中使用 一定要先注册
        tableEnv.executeSql("select id,myAvg(vc) from "+table+" group by id").print();



    }

    public static class MyAvgAcc{
        public Integer vcSum;
        public Integer vcCount;
    }

    //自定义一个类继承AggFun 通过这个函数，获取相同id的vc平均值
    public static class MyAvg extends AggregateFunction<Double,MyAvgAcc>{

        @Override
        public MyAvgAcc createAccumulator() {
            MyAvgAcc myAvgAcc = new MyAvgAcc();
            myAvgAcc.vcSum = 0;
            myAvgAcc.vcCount = 0;
            return myAvgAcc;
        }

        public void accumulate(MyAvgAcc acc,Integer value){
            acc.vcSum += value;
            acc.vcCount += 1;
        }

        @Override
        public Double getValue(MyAvgAcc accumulator) {
            return accumulator.vcSum*1D/accumulator.vcCount;
        }

    }

}
